Produced by Worcester-based VMB, the bags are 97% LDPE, but also contain a 3% metal additive, which helps the plastic break down. The Co-op claims they are as strong and safe as standard bags, and will fully degrade to carbon dioxide, water and "a small amount" of inorganic material in four years.
It is not the only major UK retailer to use degradable packaging; Tesco, Sainsbury's and Somerfield also do. However, Germany-based international association for the bioplastics and biodegradable polymers industry IBAW has recently stated that many "so-called" degradable, biodegradable and compostable packs do not deliver as promised, with little evidence that they actually decompose completely.
The association says many do not conform to the relevant European standard, EN 13432, and indeed after an initial decomposition, degradation of the remaining PE is "very slow". It also has concerns about the metal additives, claiming they can add ecotoxic and bioaccumulative substances to the environment.
Derek Davies, Co-op packaging co-ordination manager, however, remains unbowed: "Independent tests of the bags commissioned by converters clearly indicate they will degrade within four years. No degradable packaging is 100% perfect yet but its development is moving forward. In addition, the additive manufacturers say many of the catalyst metals are already found in soil.
"The IBAW seems keen on alternative, starch-based materials, which the Co-op already uses in its packaging. However, unlike in Germany, few local authorities here offer the municipal composting facilities needed to accommodate these bags. I am unsure why there seems to be a battle between the two material types. They can surely co-exist?" he says.
